An in-memory database system (IMDS) is typically a database management system that stores all, or at least most, data in main memory while storing the data on disk or SSD for durability and recovery reasons. This contrasts to traditional on-disk database systems. Because working with data in-memory is much faster than reading data from and writing data to disk systems, the IMDS can typically perform data management functions much faster and with more predictable response times than traditional database systems.
Hadoop is a distributed processing platform that allows data-intensive operations to be processed in a distributed fashion. A Hadoop cluster commonly includes a master node and a group of worker nodes. A job request may be divided into a plurality of tasks, and the tasks may be distributed to a group of worker nodes within the Hadoop platform to be processed in parallel.